In building construction, different types of panels for forming interior and exterior walls and ceilings are used. Typically, the panels are in the form of boards (also referred to as panels) affixed to framing members such as in balloon framing arrangements known in the art. Examples include gypsum board faced with paper also known as wallboard or drywall, paperless gypsum panels prepared with fibrous mats (e.g., fiberglass), and the like. These and other types of boards are typically cut to appropriate dimensions and then fastened to framing members, e.g., with screws, nails, or the like to form wall sections formed from multiple boards.
Two side-by-side panels disposed in the same plane will form a joint seam between them on vertical walls and horizontal ceilings. In prior art, to finish the seam, joint reinforcement tape is embedded in the seam, along with a layer of joint compound under the tape, and multiple coats of joint compound applied over the tape. U.S. Pat. Nos. 2,850,404 and 6,668,897 relate to joint reinforcement tape and methods in which joint seams are finished with joint reinforcement tape.
Some panels meet at an angle such as when forming a corner. Reinforcement bead can be utilized to hide the corner seam and to protect the corner. Reinforcement bead can be directly attached to the panel using fasteners, or a layer of joint compound is applied under the trim to adhere the reinforcement bead to the panel. The installed reinforcement is then concealed with multiple layers of joint compound applied over the trim. Fasteners used to affix the panel to framing members must also be concealed with multiple layers of joint compound applied over them. After the various joint compound applications are dried, the resulting wall surfaces can be sanded and painted to form the desired uniform and aesthetically pleasing appearance. U.S. Pat. No. 8,931,230 to United States Gypsum Company discloses a method in which only one coat of joint compound is applied.
In gypsum drywall construction, paper tape is commonly used to bridge the seam between adjacent gypsum panels. The paper tape is embedded into joint compound, and then concealed by subsequent coats of joint compound to create a monolithic surface. The function of the tape in the system is to bridge the adjacent panels and to provide strength and reinforcement to the joint.
The taping operation involves several repetitive steps making it a time-consuming process in drywall finishing. One taping process is using a mechanical tool commonly referred to as a bazooka which is fitted with a roll of paper tape and filled with ready mixed joint compound which has been mixed with sufficient water so that the compound is fluid and flows easily. One of such applications is provided in U.S. Pat. No. 6,378,738. As the head of the bazooka is placed over the joint and moved down the wall, the tape advances and the backside is coated with a thin coat of joint compound which holds it loosely to the wallboard. A second worker will likely have to follow behind the bazooka wiping the tape tight to the wall and removing excess joint compound from over the tape. This operation occurs over every seam where gypsum panels are joined.
Aside from the tedium of the application process, if the joint compound does not flow evenly over the back side of the tape, blisters may occur which are often not seen until the taping coat is dry. In this case, a worker must cut the tape away from the joint and reapply a thin film of joint compound and piece of tape prior to moving on to the next step of finishing.